The Intrinsic Rate of Natural Increase of Irradiated Peromyscus in the Laboratory

Ecology ◽  
1968 ◽  
Vol 49 (6) ◽  
pp. 1172-1179 ◽  
Author(s):  
Norman R. French ◽  
Howard W. Kaaz
Keyword(s):  
Intrinsic Rate ◽  
Natural Increase

Influence of temperature on life history traits of the free-living, bacterial-feeding nematode Panagrolaimus sp. strain NFS-24

Nematology ◽  
2013 ◽  
Vol 15 (8) ◽  
pp. 939-946 ◽  
Author(s):  
Farhana Ayub ◽  
Olaf Strauch ◽  
Laurent Seychelles ◽  
Ralf-Udo Ehlers
Keyword(s):  
Intrinsic Rate ◽  
Analysis Data ◽  
Natural Increase ◽  
Population Doubling ◽  
Food Density ◽  
Hanging Drop ◽  
Free Living ◽  
Single Male ◽  
Different Temperatures ◽  
Hanging Drop Method

Life cycle analysis data of the free-living, bacterial-feeding Panagrolaimus sp. strain NFS 24-5 were assessed at different temperatures using a hanging drop method with single male and female individuals and a food density of 3 × 109 Escherichia coli cells ml−1. Lifespan at the moment when the first egg was laid was 5.7 days at 21°C and 4 days at 25, 27 and 29°C. The intrinsic rate of natural increase () was 0.53 at 21°C, 0.81 at 25°C, 0.93 at 27°C and 0.81 at 29°C, corresponding to population doubling times () of 1.3, 0.9, 0.7 and 0.9 days, respectively. Over 200 offspring per female were produced at 27°C. All other temperatures yielded fewer offspring. When females were kept without males, the life span was 49 days, whereas the last reproductive female (hanging drop with male individual) died after 16.5 days. These data will contribute to the interpretation of nematode population dynamics recorded in liquid culture.

Life cycle and calculation of the intrinsic rate of natural increase of two bacterivorous nematodes, Panagrolaimus sp. and Poikilolaimus sp. from chemoautotrophic Movile Cave, Romania

Nematology ◽  
2007 ◽  
Vol 9 (2) ◽  
pp. 271-284 ◽  
Author(s):  
Daniel Muschiol ◽  
Walter Traunspurger
Keyword(s):  
Life Cycle ◽  
Body Length ◽  
Generation Time ◽  
Microbial Mats ◽  
Somatic Growth ◽  
Intrinsic Rate ◽  
Reproductive Rate ◽  
Natural Increase ◽  
Net Reproductive Rate ◽  
Movile Cave

AbstractThe life cycle and somatic growth of two bacterivorous nematodes, Panagrolaimus sp. and Poikilolaimus sp., isolated from chemoautotrophic microbial mats in Movile Cave, Romania, were studied in monoxenic cultures at 20°C with Escherichia coli as the food source. A method is described that allows simultaneous investigation of the somatic growth pattern, age-specific fecundity, and age-specific mortality of single individuals with high accuracy. Somatic growth curves of the species are presented. During juvenile development, both species showed a strict linear increase in body length, whereas body weight increased exponentially. Growth was continuous without lag phases. The relationships between fresh weight, W (μg), and body length, L (mm), were W = 1.6439L2.7672 for Poikilolaimus sp. and W = 0.2085L4.0915 for Panagrolaimus sp. Life tables and fecundity schedules for the two species are presented. In addition, demographic parameters were calculated. For Panagrolaimus, the intrinsic rate of natural increase (rm), calculated according to the Lotka equation, was 0.309, the net reproductive rate (R0) 64, the mean generation time (T) 13.8 days and the minimum generation time (Tmin) 9.5 days. The corresponding values for Poikilolaimus were rm = 0.165, R0 = 108, T = 26.2 and Tmin = 19.5. Panagrolaimus produced fewer progeny than Poikilolaimus during its life but exhibited faster population growth due to its faster maturation. It showed a distinct post-reproductive period, whereas Poikilolaimus remained fertile until death.

EFFECTS OF CONSTANT TEMPERATURE, RELATIVE HUMIDITY, AND SIMULATED RAINFALL ON DEVELOPMENT AND SURVIVAL OF THE SPRUCE SPIDER MITE (OLIGONYCHUS UNUNGUIS)

1983 ◽  
Vol 115 (1) ◽  
pp. 93-105 ◽  
Author(s):  
John V. Boyne ◽  
Fred P. Hain
Keyword(s):  
Relative Humidity ◽  
Intrinsic Rate ◽  
Developmental Time ◽  
Reproductive Rate ◽  
Natural Increase ◽  
Simulated Rainfall ◽  
Net Reproductive Rate ◽  
Fraser Fir ◽  
Oligonychus Ununguis ◽  
Rate Of Increase

AbstractExperiments were conducted on Fraser fir, Abies fraseri (Pursh) Poir, seedlings or cut terminals. Results indicate that Oligonychus ununguis (Jacobi) responds most favorably to temperatures approximating 26 °C and to relative humidity levels approaching 50 to 60%. Developmental time, time to 50% mortality, net reproductive rate, mean generation time, intrinsic rate of natural increase, finite rate of increase, and days for populations to double were computed for each temperature and relative humidity regime. Simulated rainfall severely limits population density on Fraser fir seedlings.

Life history and feeding biology of the predatory thrips, Aleurodothrips fasciapennis (Thysanoptera: Phlaeothripidae)

1998 ◽  
Vol 88 (3) ◽  
pp. 351-357 ◽  
Author(s):  
D.M. Watson ◽  
T.Y. Du ◽  
M. Li ◽  
J.J. Xiong ◽  
D.G. Liu ◽  
...  
Keyword(s):  
Life History ◽  
Relative Humidity ◽  
Sex Ratio ◽  
Intrinsic Rate ◽  
Natural Increase ◽  
Adult Longevity ◽  
Female Fecundity ◽  
Adult Sex Ratio ◽  
Survival And Reproduction ◽  
Low Humidity

AbstractDetails of the life history, the effects of relative humidity and temperature on survival and reproduction, and the predatory ability of Aleurodothrips fasciapennis Franklin were examined under laboratory conditions. Stage-specific development and adult longevity were similar between sexes, and the adult sex ratio was 1:1. Females laid 23.3 ± 18.0 eggs of which 83% hatched. The survival rate of first instars to adulthood was 82%. The intrinsic rate of natural increase (rm) was 0.04, assuming a zero or 5.4 day pre-oviposition interval. Temperature did not affect the proportion of eggs that hatched, the proportion of first instars surviving to adulthood or adult sex ratios. However, female fecundity was dependent on temperature being highest at 24 ndash 28°C. Relative humidity did not affect adult sex ratio or female fecundity but the proportion of eggs hatched and the survival of first instars to adulthood increased as relative humidity increased. Few eggs hatched when relative humidity was <65%. Larval and adult female A. fasciapennis were voracious feeders but the number of prey killed per progeny was high, suggesting A. fasciapennis was inefficient at converting prey into progeny biomass. The potential value of A. fasciapennis as a biocontrol agent of Aonidiella aurantii (Maskell) on Australian citrus is discussed in terms of its rm, prey killing power and environmental adaptability. It is concluded that population growth of A. fasciapennis should exceed that of A. aurantii under field conditions but A. fasciapennis may be of little value against A. aurantii on citrus grown under conditions of high temperature and low humidity, or when prey densities are low.

Intrinsic Rate of Natural Increase of Five Species of Ischnoceran Lice (Insecta: Phthiraptera) from India

2009 ◽  
Vol 120 (4) ◽  
pp. 363-369 ◽  
Author(s):  
Arun Kumar Saxena ◽  
Nidhi Gupta ◽  
Sandeep Kumar ◽  
Vikram Khan ◽  
Gaurav Arya ◽  
...  
Keyword(s):  
Intrinsic Rate ◽  
Natural Increase

A demographic study of the life cycle of Tisbe furcata (Baird, 1837) (Copepoda: Harpacticoida)

1981 ◽  
Vol 61 (3) ◽  
pp. 691-705 ◽  
Author(s):  
Marc Bergmans
Keyword(s):  
Life Cycle ◽  
Generation Time ◽  
Harpacticoid Copepod ◽  
Intrinsic Rate ◽  
Reproductive Rate ◽  
Natural Increase ◽  
Net Reproductive Rate ◽  
Life Table Data ◽  
Table Data ◽  
Stable Stage

The life-cycle of the harpacticoid copepod Tisbe furcata (Baird, 1837) at 18 C was studied quantitatively. Stage durations were determined by two different methods, using synchronous cohorts. Combined nauplius stages last for 80·4 h; the successive copepodite stages take 23·0, 23·2, 28·0 (♀) to 23·2 (♂), 33·4 (♀) to 24·2 (♂) and 48·8 (♀) to 34·7 (♂) h, respectively. Females develop more slowly but more synchronously than males. Age-specific survival and fertility rates were used to calculate the stable stage distribution in an exponentially growing population. From life-table data the following demographic parameters were computed: intrinsic rate of natural increase rm = 0·233 day−1; net reproductive rate Ro = 94; minimum generation time Tmin = 14·9 days; parameters related to ‘generation time’: T = 19·5 days, = 16·4 days, Tc = 25·4 days.

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